There is currently an ongoing drive toward the downscaling of device dimensions in virtually all aspects of electronic device manufacture. Smaller electronic devices tend to be more popular than larger, more bulky devices when both devices have substantially equivalent capabilities. Accordingly, being able to fabricate smaller components would clearly tend to facilitate the production of smaller devices that incorporate those components. However, many modern electronic devices require electronic circuitry to perform both actuation functions (e.g., switching devices) and data processing or other decision making functions. The use of low-voltage complementary metal-oxide-semiconductor (CMOS) technologies for these dual functions may not be practical. Thus, high-voltage integrated circuits (HVIC) or power-integrated circuits (PIC) have been developed to attempt to integrate high-voltage device structures with low voltage device structures on a single chip.
Some examples of devices that involve switching at relatively high-voltage levels include drivers for flat panel displays, lighting and ballast applications (e.g., light emitting diode (LED) lighting), power supplies (e.g., mobile device chargers), and numerous other products. The high-voltage MOS devices that are desirable for employment in these applications should desirably possess a high breakdown voltage, such as to prevent punch through from a high-voltage area to a low-voltage area, but also have a relatively low on-resistance.
Power devices may typically be categorized as being either vertical or lateral devices. Devices employing a vertical structure have a current path that flows from the top of the device to the bottom of the device via a substrate. Devices employing a lateral structure have a current path that enters and leaves the chip (integrated circuit) through the same surface (e.g., the upper surface of the chip). The lateral structure may allow implementation of different types and multiple numbers of lateral devices on the same substrate. However, doing so may only be effective with electrical isolation.